1. Field of the Invention
The present invention relates to a resist pattern that can form a fine pattern (fine traces) useful for manufacturing magnetic heads, semiconductor devices, and other electronic devices, to a process for forming a resist pattern which can efficiently form the resist pattern in a short time, to a positive type resist composition that is useful for the formation of the resist pattern, is typically useful as a material for an upper resist in a two-layer resist process using i-line radiation and can contribute to a higher integration of electronic devices, to an alkali-soluble siloxane polymer that is useful for the positive type resist composition, to an electronic device having a fine pattern (fine traces) formed by the use of the resist pattern, and to a process for manufacturing an electronic device which enables efficient manufacture of the electronic device in a short time.
2. Description of the Related Art
Resist processes have been often used in manufacturing semiconductor devices, magnetic bubble memory devices, surface bubble memory devices, and other electronic devices having a fine pattern (fine traces). Positive type resist compositions generally have higher resolution than negative resist compositions (e.g., Japanese Patent Application Laid-Open (JP-A) No. 03-103855 and JP-A No. 05-53316). Certain compositions containing an alkali-soluble resin having photosensitivity to radiation having wavelengths of 300 nm to 500 nm and a compound having a quinonlediazido group are known as such positive type resist compositions (e.g., JP-A No. 05-53316). With increasing densities of electronic devices and with increasing layers of wiring thereof, the heights of steps on the surface of substrates increase. Thus, conventional single-layer resist processes cannot yield sufficient resolution even by using the positive type resist compositions.
Under these circumstances, a two-layer resist process has been proposed, in which an organic resin layer as an underlying layer is formed to flatten steps on a substrate; a thin film of a resist layer as an upper layer is formed on the organic resin layer, is patterned to form an upper pattern, and the upper pattern is transferred to the lower layer by oxygen plasma etching. The two-layer resist process can significantly improve the resolution, since the underlying layer can flatten the steps on the substrate and can prevent light reflection from the substrate, and the upper layer can be formed as a thin layer. Organosilicon polymers that are highly resistant to oxygen plasma have been used as the material for the upper resist layer in the two-layer resist process, since the upper resist layer is subjected to oxygen plasma etching. However, from the viewpoint of obtaining high quality electronic devices, a demand has been made on materials for a resist layer to be excellent in resolution and storage stability as well as oxygen plasma resistance.
When a resist film prepared from a resist composition including a silicon-containing polymer is patterned using a halftone mask, a ghost pattern called “side lobe” is formed on the periphery of a target resist pattern. The side lobe is formed by action of light transmitting through a halftone portion in the halftone mask. Therefore, a demand has also been made on the resist composition to overcome the aforementioned problem.
An organosilicon compound and a positive type resist composition containing thereof, that has high oxygen plasma resistance and can form a resist film with fewer side lobes when it is patterned using a halftone mask, has not been provided yet.